package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;

/** This class implements {@link InvertedDocConsumer}, which
 *  is passed each token produced by the analyzer on each
 *  field.  It stores these tokens in a hash table, and
 *  allocates separate byte streams per token.  Consumers of
 *  this class, eg {@link FreqProxTermsWriter} and {@link
 *  TermVectorsTermsWriter}, write their own byte streams
 *  under each term.
 */
final class TermsHash extends InvertedDocConsumer {

    final TermsHashConsumer consumer;
    final TermsHash nextTermsHash;
    final DocumentsWriter docWriter;

    boolean trackAllocations;

    public TermsHash(final DocumentsWriter docWriter, boolean trackAllocations, final TermsHashConsumer consumer, final TermsHash nextTermsHash) {
        this.docWriter = docWriter;
        this.consumer = consumer;
        this.nextTermsHash = nextTermsHash;
        this.trackAllocations = trackAllocations;
    }

    @Override
    InvertedDocConsumerPerThread addThread(DocInverterPerThread docInverterPerThread) {
        return new TermsHashPerThread(docInverterPerThread, this, nextTermsHash, null);
    }

    TermsHashPerThread addThread(DocInverterPerThread docInverterPerThread, TermsHashPerThread primaryPerThread) {
        return new TermsHashPerThread(docInverterPerThread, this, nextTermsHash, primaryPerThread);
    }

    @Override
    void setFieldInfos(FieldInfos fieldInfos) {
        this.fieldInfos = fieldInfos;
        consumer.setFieldInfos(fieldInfos);
    }

    @Override
    public void abort() {
        try {
            consumer.abort();
        } finally {
            if (nextTermsHash != null) {
                nextTermsHash.abort();
            }
        }
    }

    @Override
    synchronized void flush(Map<InvertedDocConsumerPerThread, Collection<InvertedDocConsumerPerField>> threadsAndFields, final SegmentWriteState state) throws IOException {
        Map<TermsHashConsumerPerThread, Collection<TermsHashConsumerPerField>> childThreadsAndFields = new HashMap<TermsHashConsumerPerThread, Collection<TermsHashConsumerPerField>>();
        Map<InvertedDocConsumerPerThread, Collection<InvertedDocConsumerPerField>> nextThreadsAndFields;

        if (nextTermsHash != null)
            nextThreadsAndFields = new HashMap<InvertedDocConsumerPerThread, Collection<InvertedDocConsumerPerField>>();
        else
            nextThreadsAndFields = null;

        for (final Map.Entry<InvertedDocConsumerPerThread, Collection<InvertedDocConsumerPerField>> entry : threadsAndFields.entrySet()) {

            TermsHashPerThread perThread = (TermsHashPerThread) entry.getKey();

            Collection<InvertedDocConsumerPerField> fields = entry.getValue();

            Iterator<InvertedDocConsumerPerField> fieldsIt = fields.iterator();
            Collection<TermsHashConsumerPerField> childFields = new HashSet<TermsHashConsumerPerField>();
            Collection<InvertedDocConsumerPerField> nextChildFields;

            if (nextTermsHash != null)
                nextChildFields = new HashSet<InvertedDocConsumerPerField>();
            else
                nextChildFields = null;

            while (fieldsIt.hasNext()) {
                TermsHashPerField perField = (TermsHashPerField) fieldsIt.next();
                childFields.add(perField.consumer);
                if (nextTermsHash != null)
                    nextChildFields.add(perField.nextPerField);
            }

            childThreadsAndFields.put(perThread.consumer, childFields);
            if (nextTermsHash != null)
                nextThreadsAndFields.put(perThread.nextPerThread, nextChildFields);
        }

        consumer.flush(childThreadsAndFields, state);

        if (nextTermsHash != null)
            nextTermsHash.flush(nextThreadsAndFields, state);
    }

    @Override
    synchronized public boolean freeRAM() {
        return false;
    }
}
